diff --git a/libraries/AP_Mount/AP_Mount.h b/libraries/AP_Mount/AP_Mount.h
index 89c576a729..b8333ea339 100644
--- a/libraries/AP_Mount/AP_Mount.h
+++ b/libraries/AP_Mount/AP_Mount.h
@@ -20,8 +20,9 @@
 #ifndef AP_Mount_H
 #define AP_Mount_H
 
-//#include <AP_Common.h>
+#include <FastSerial.h>
 #include <AP_Math.h>
+#include <AP_Common.h>
 #include <AP_GPS.h>
 #include <AP_DCM.h>
 #include <GCS_MAVLink.h>